An autonomous mobile robot is required to be capable of moving about in an area where various obstacles are placed from a current position to a destination in a smooth manner while avoiding the obstacles. To provide such a capability to a robot, it has been proposed to prepare an obstacle database containing information on the positions of obstacles in a map of a designated area according to visual information obtained by the robot, and program the route for the robot by looking up the database. See Japanese patent laid open publication No. 2003-266345.
However, a designated area may not have any pre-defined passages as is the case with showrooms and performance stages, and it is not easy to designate a route for the robot when only the destination is given. The shortest route from the current position to a destination would be given by a straight path connecting these two points. However, when an obstacle is located on such a path, it has been customary for a robot to slightly change the straight path by coming close to the obstacle and passing around the obstacle in the immediate vicinity. This obviously is not the shortest path for the robot to move from the current position to the destination. Furthermore, the robot would make a clumsy appearance.
It may be conceivable to program the robot so as to make use of the visual information obtained by the robot and make a more intelligent decision. However, it would require a highly complex algorithm and increase the computing load. This would cause a delay in the reaction of the robot and increase the power consumption of the computer. As a mobile robot typically relies on a battery for its power, a large power consumption is highly undesirable.